Heteroatom-Containing Silane Resins

Abstract

The invention relates to oligomers of silane compounds having at least one hydrolysable group and at least one heteroatom bridged to a silicon atom via a sp 2 -hybridized quaternary carbon atom, as defined herein, a process for preparing such silane compound resins, the use thereof, for example as end-capping agent, crosslinker, and/or adhesion promoter in curable compositions, and curable compositions containing these resins as well as the use of such compositions.

1 . A silane resin obtainable by condensation of at least one first silane of formula Si(R A )(R 4 )(R 1 ) 2  with at least one second silane of formula Si(R A )(R 1 ) 3 , wherein the first silane, the second silane or both are selected from silanes of general formula (I) containing at least one heteroatom bridged to a silicon atom via an sp 2 -hybridized quaternary carbon atom: 
       
         
           
           
               
               
           
         
         wherein 
         k is 0 or 1; 
         q is 0, 1, 2 or 3; 
         each R 1  is independently selected from a hydrolyzable group; 
         each R 4  is independently selected from hydrogen or a linear or branched, substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms optionally comprising at least one heteroatom; 
         X is a divalent or polyvalent heteroatom; 
         each R 5  is independently selected from oxygen, hydrogen, or a linear or branched, substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms optionally comprising at least one heteroatom; 
         R 2  is selected from a linear or branched, substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms optionally comprising at least one heteroatom; 
         R 3  is selected from hydrogen or a linear or branched, substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms optionally comprising at least one heteroatom; at least one heteroatom or R 2  and R 3  form a cyclic structure; and 
         R A  is —C(═R 2 )—X(R 3 )(R 5 ) q  or is selected from C 1  to C 20  alkyl, C 4  to C 8  cycloalkyl or C 5  to C 20  aryl groups, optionally comprising at least one heteroatom. 
       
     
     
         2 . The silane resin of  claim 1 , wherein the first and the second silane are silanes of formula (I) with R A  being —C(═R 2 )—X(R 3 )(R 5 ) q . 
     
     
         3 . The silane resin of  claim 1 , wherein the silane of the general formula (I) is a heterocycle-containing silane of general formula (I-A) 
       
         
           
           
               
               
           
         
         wherein 
         R 1 , R 4 , R 5 , X, k and q are as defined for said general formula (I); and 
         R 6 , R 7  and R 8  are same or each independently different from one another, and selected from hydrogen, a hydroxy group, or a linear or branched, substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms selected from alkyl, cycloalkyl or aryl groups, which optionally contain at least one heteroatom, selected from O, N, S or Si. 
       
     
     
         4 . The silane resin of  claim 1 , wherein
 (1) each R 1  is independently selected from the group consisting of alkoxy, carboxy, oxime, amino, amido, lactato, alkenoxy, and acetoxy groups; and/or   (2) R 4  is selected from hydrogen, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, vinyl, phenyl, C 2  to C 12  alkenyl, or C 5  to C 12  aryl groups, which optionally comprise at least one heteroatom; trifluoropropyl, aminopropyl, or pyridinyl group   (3) X is selected from O or S; and/or   (4) R 6 , R 7  and R 8  are selected from hydrogen, or C 1  to C 20  alkyl, C 4  to C 8  cycloalkyl or C 6  to C 20  aryl groups which optionally comprise at least one heteroatom.   
     
     
         5 . The silane resin of  claim 4 , wherein
 (1) in the compounds of general formula (I-A), X is S, q is 0, R 6 , R 7  and R 8  are hydrogen, R 4 , if present, is selected from vinyl, trifluoropropyl, aminopropyl, and pyridinyl groups;   and all R 1  are methoxy or ethoxy; and/or   (2) the first silane is a compound of formula (I-A) wherein k is 1, X is S, q is 0, R 6 , R 7  and R 8  are hydrogen, R 4  is vinyl and all R 1  are methoxy or ethoxy; and/or   (3) the second silane is a compound of formula (I-A) wherein k is 0, X is S, q is 0, R 6 , R 7  and R 8  are hydrogen, and all R 1  are either methoxy or all are ethoxy.   
     
     
         6 . The silane resins of  claim 1 , wherein
 (1) the first silane and the second silane are used in molar ratios of about 2:1 to about 1:50; and/or   (2) the molecular weight of the resin is in a range of M n >200 to 1200 and/or M w >200 to 1500; and/or   (3) the resins comprise, on average, 2 to 10 monomeric units.   
     
     
         7 . A curable composition comprising
 (A) at least one curable polymer;   (B) at least one silane resin according to  claim 1 ; and   (C) optionally at least one curing catalyst.   
     
     
         8 . The curable composition of  claim 7 , wherein the at least one curable polymer (A) is a moisture-curable polymer selected from the group consisting of silane-modified polymers and silicones. 
     
     
         9 . The curable composition of  claim 8 , wherein the at least one curable polymer (A) is a polydimethylsiloxane (PDMS). 
     
     
         10 . The curable composition of  claim 7 , wherein the curable polymer (A) comprises at least one terminal group of formula (II):
   -A-Si(R a ) p (OR b ) 3-p   (II)
   wherein:   p is 0, 1 or 2;   A is a bond, or —O— or a linear, branched or cyclic divalent group selected from hydrocarbon residues having 1 to 12 carbon atoms, alkylene, arylene, oxyalkylene, oxyarylene, siloxane-alkylene, siloxane-arylene, ester, amine, glycol, imide, amide, alcohol, carbonate, urethane, urea, sulfide, ether or a derivative or combination thereof;   each R a  is independently selected from the group consisting of hydrogen, halogen, amino, oximino, a substituted or unsubstituted alkyl, alkenyl, alkenyloxy, alkynyl, alkylnyloxy, cycloaliphatic, cycloaliphatic-O—, aryl, aryloxy, heteroaryl, heteroaryloxy, heteroalicyclic, heteroalicyclicoxy, acyl, acyloxy group or a combination thereof;   each R b  is independently selected from H, C 1 -C 8  alkyl, C 1 -C 8  acyl, a group of general formula (IIIa) or a group of general formula (IIIb):
   —Y—COOR c   (IIIa)
 
   —Y—CONR d R e   (IIIb)
 
   wherein   Y is a substituted or unsubstituted (hetero)aromatic group having 4 to 14 ring atoms, a substituted or unsubstituted saturated or partially unsaturated 4- to 14-membered (hetero)cyclic group or —(C(R f ) 2 ) s —;   R c  is a substituted or unsubstituted alkyl, alkenyl, alkynyl, cycloaliphatic, aryl, heteroaryl, and heteroalicyclic group or a combination thereof;   each R f  is independently selected from the group consisting of hydrogen, a substituted or unsubstituted alkyl, alkenyl, alkynyl, cycloaliphatic or aryl group; and   s is an integer from 1 to 10;   R d  is selected from the group consisting of hydrogen, a substituted or unsubstituted alkyl, alkenyl, alkynyl cycloaliphatic, aryl, heteroaryl, and heteroalicyclic group or a combination thereof or R e ;   R e  is a group of general formula (IV):
   —R g —SiR h   r (OR i ) 3-r   (IV)
 
   wherein   R g  is an alkylene group, optionally interrupted by a heteroatom;   each R h  is independently selected from the group consisting of hydrogen, halogen, amino, a substituted or unsubstituted alkyl, alkenyl, alkynyl, cycloaliphatic, aryl, heteroaryl, and heteroalicyclic group or a combination thereof;   each R i  is independently selected from the group consisting of a substituted or unsubstituted alkyl, alkenyl, alkynyl, or acyl group; and   each r independently represents 0, 1, or 2.   
     
     
         11 . The curable composition of  claim 10 , wherein
 (i) each R b  is independently H, C 1 -C 2  alkyl, C 2  acyl or a group of the general formula (IIIa); and/or   (ii) p is 0 or 1; and   each R b  is independently acetyl, ethyl, methyl or a group of general formula (IIIa), wherein R c  is a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms; and Y is a substituted or unsubstituted aromatic group having 6 carbon ring atoms or —(C(R f ) 2 ) s —, wherein s is 1 and a first R f  group is hydrogen and a second R f  group is a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, wherein the alkyl group is methyl, carboxymethyl or an (alkyl) ester thereof; and/or   (iii) A is a bond, —O— or a linear or branched divalent group selected from siloxane-alkylene.   
     
     
         12 . The curable composition of  claim 11 , wherein the group of formula (IIIa) is a lactic acid ethyl ester group or a malic acid mono- or diester group; and/or
 (iii) A is a bond, —O— or a linear or branched divalent group of the formula —(CH2)1-10-(Si(Alk)2-O—Si(Alk)2)1-10-(CH2)1-10, or a derivative thereof, with Alk being unsubstituted C1-10 alkyl; and   the curing catalyst is a tin compound.   
     
     
         13 . The curable composition of  claim 12 , further comprising one or more additional ingredients selected from the group consisting of plasticizers, fillers, bases, and adhesion promoters different from (B). 
     
     
         14 . A moisture-curable composition containing an end-capping agent, crosslinker, and/or adhesion promoter which comprises the silane resin according to  claim 1 . 
     
     
         15 . An adhesive, sealing, or coating material comprising the composition according to  claim 7 . 
     
     
         16 . The silane resin of  claim 1 , wherein:
 each R 1  is independently selected from alkoxy, carboxy, oxime, amino, amido, lactato, alkenoxy, and acetoxy groups,   each R 4  is independently selected from C 1  to C 20  alkyl, C 2  to C 20  alkenyl, C 5  to C 20  aryl, C 7  to C 20  alkaryl, or C 7  to C 20  aralkyl groups, at least one of which comprises at least one heteroatom selected from O, N, S, P, Si, Cl, Br, I or F;   X is a divalent or polyvalent heteroatom;   each R 5  is independently selected from C 1  to C 20  alkyl, C 4  to C 8  cycloalkyl or C 6  to C 20  aryl groups, which contain by at least one heteroatom;   R 2  is selected C 1  to C 20  alkyl, C 2  to C 20  alkenyl, C 6  to C 20  aryl, C 7  to C 20  alkaryl or C 7  to C 20  aralkyl groups, which optionally contain at least one heteroatom,   R 3  is selected from a linear or branched, substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms, wherein R 2  and R 3  form a cyclic structure; and   R A  is —C(═R 2 )—X(R 3 )(R 5 ) q  or is selected from C 1  to C 20  alkyl, C 4  to C 8  cycloalkyl or C 5  to C 20  aryl groups, which optionally contain at least one heteroatom.   
     
     
         17 . The silane resin of  claim 16 , wherein the cyclic structure formed by R 2  and R 3  is a substituted or unsubstituted 5- to 10-membered (hetero)cyclic hydrocarbon structure containing the heteroatom X as part of the ring. 
     
     
         18 . The silane resins of  claim 16 , wherein
 (1) the first silane and the second silane are used in molar ratios of about 1:1 to about 1:20; and/or   (2) the molecular weight of the resin is in a range of M n >250 to 600, and/or M w >250 to 800; and/or   (3) the resins comprise, on average, 2 to 8 monomeric units.   
     
     
         19 . A method of end-capping, crosslinking, and/or promoting adhesion of a moisture-curable composition comprising the step of adding the silane resin according to  claim 1  to said moisture-curable composition.